/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/OnlinePartyInterface.h
Get a list of currently joined parties for the user
true if entries found
bool GetJoinedParties ( const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & LocalUserId, [TArray](API\Runtime\Core\Containers\TArray)< [TSharedRef](API\Runtime\Core\Templates\TSharedRef)< const [FOnlinePartyId](API\Plugins\OnlineSubsystem\FOnlinePartyId) >> & OutPartyIdArray ) const